Google is in the process of killing their Google Buzz platform. The company has already stopped accepting new third party authorizations for the Buzz platform.
Dlvr.it is one of the many services that have supported Google Buzz for a long time now. They have now discontinued support for the Buzz platform.
Users can no longer auto publish to Google Buzz using dlvr.it.
This should not affect many users. It remains to be seen how soon Dlvr.it gets support for Google Plus which has practically become the social offering from the search engine giant.